html,body {
    height: 100%;
}
@media only screen and (min-width: 480px){
    body {
        background: yellow;
    }
}
@media only screen and (min-width: 640px) and (max-width: 1024px) {
    body {
        background: green;
    }
}
@media screen and (min-width: 1024px){
    body {
        background: blue;
    }
}